Can one of you kind people provide a list of Mod specific files that must be transferred or copied from a track present during the mod install into a new track that is being installed or replaced after a mod install? I have a good clue just by doing side by side comparison but an official list by a mod author would be reassuring... Thanks in Advance...

Sometimes, the files that command the AIs behaviour ( like min race, max race ect..) have been edited to match the drivxx .ini files specific to a carset modifications .
There can be modification on the starting grids arrangements and on the pits stall. If yes, as you know, you need to back up your track folder, and install another track folder.

But usually, with the latest carsets , you have only to drop down the track specific files that come with the carset installer on your existing installed track.

1.) track.ini must be in the track folder even if there is a trackxx.ini - otherwise replay files for this track will not appear on the Replay screen.
2.) sometimes page0.pbf must be in the track folder even if there is a pagxx.pbf - sometimes a track program cover will not show up.
3.) use of AI track files other than xxxx.lp (such as race.l66) is not advised.